Re: New issue - Meaning of URIs in RDF documents

  This depends on what you mean by "contexts". If you mean that I can send one person an email saying (in RDF) 
  <http://example.com/foo.rdf#bar> pantone:color "blue426" .
  and it can mean one thing and I send it to another person it can mean something else,
  then we do not have system of communication which has any properties at all.



Exactly.

Pat, we've had this discussion at length several times before. 

Your assertion that the RDF MT does not presume a single interpretation
is quite correct. Any such constraint would make RDF useless to a
wide number of applications which are not part of the semantic web. And
even though RDF is a foundational component of the semantic web,
its use is certainly not limited only to the semantic web.

It is the SW Architecture that asserts the presumption of a single shared
interpretation, of a virtual, ever changing, global graph consisting of all 
statements accessible as part of that semantic web of knowledge.

All agents operating on knowledge which is "on the semantic web" 
are committing to presume and honor , as well as possible, a single 
interpretation of that  virtual, global graph of statements.

This is one benefit of having a standardized mechanism for accessing
statements which are "on the semantic web" such as URIQA as it
provides an explicit mechanism by which that commitment is expressed.

Any agent obtaining descriptions of resources using the URIQA extensions
is explicitly agreeing, by that act, to presume a single shared interpretation of
all statements on the semantic web and honor the authoritative semantics 
ascribed to any resource as exposed in its authoritative URIQA accessible 
description.

Any knowledge producer exposing descriptions of resources using the
URIQA extensions is explicitly agreeing, by that act, to presume a single
shared interpretaion of all statements on the semantic web and honor the
authoritative semantics ascribed to any resource as exposed in its 
authoritative URIQA  accessible description.

There will be other uses of RDF, OWL, and related SW technologies which
will not be part of the Semantic Web. But all agents, systems, models,
operations, etc. which are part of the Semantic Web *must* presume
a single shared interpretation of  all statements,  and a consistent, 
unambiguous  denotation for each URI.

Does that mean that there won't be noise, errors, bugs, contradictions, 
etc on the semantic web? Of course not. And in fact, without this
fundamental presumption of a single common interpretation, one
is not even able to detect or assert the presence of any contradictions,
since one can simply conclude that all statements are valid/true,
based on any arbitrary number of interpretations.

Without the presumption of a single consistent interpretation for all
semantic web knowledge, the semantic web is completely useless
as to its intended purpose.

Regards,

Patrick

--

Patrick Stickler
Nokia, Finland
patrick.stickler@nokia.com